Portable dynamo.



No. 844,991. PATENTED FEB. 19, 1907.

. G. A. ALLEN.

PORTABLE DYNAMO.

APPLIOATIO N FILED 1336.3,1906.

Mumum,

W/TNESSES INVENTOH WW L610 ATTOHNEyS UNITED sTATEs PATENT GEORGE ADINALLEN, or WEsTEEu srRiNes, ILLINOIS, ASSIGNOR TOTHE AETNA POWDERCOMPANY, or CHICAGO, itniuois, A CORPORATION OF INDIANA.

PORTABLE D'YNAMO.

Specification of Letters Patent.

Patented Feb. 19, 1907.

Application filed December 3, 1906. .Serial No. 846,139-

- To all whom it may concern.-

ble of being operated Be it known that I, GEORGE ADIN ALLEN, a citizenof the United States, and a resident of Western Springs, in the countyof Cook and State of Illino1s, have invented a new and Improved PortableDynamo, of which the following is a full, clear, and exact descrip--tion. I

This invention relates to certain improvements in portable dynamos,andmore particularly to that type of dynamo used in blasting operationsforexploding the blasting charges.

The object of the invention is to provide a ignite the electric fuseswhich are used in exploding the dynamite or other explosive. The type ofthe device in which the rack-bar is pushed down to rotate the armaturehas been found far more advantageous in use than any other type and hassurvived all others for a large number of years.- Thelarge increase inblasting operations, especially in stone-quarries and in railroadconstruction, has resulted in the demand for larger blasting-machines inorder that a greater number of charges might be fired simultaneously.

This demand was at first met by the produc-' tion of a machinecapable offiring from forty to fifty fuses at a time, and this machine has beenfor a number of years considered to have the maximum capacity v one manand at the same time of a size an Wei ht which would make it easilyportable, an therefore commercially valuable. I,

Numerous devices for using gearing-to gain the required number of revoutions of the armature while keeping the length of the rackbar withinreasonable limits were tried and of any machine capafoundunsatisfactory, because they were too complicated for the ordinaryworkmen to keep in repair. The current from the electric-lighting dynamoor similar machine could not be used generally, because it required theservices of ail-electrician to lay the blasting-wires, inasmuch as theelectriclighting dynamo requires a much more com plicated system ofwiring. The only choice the manufacturers had, therefore, in the attempt -to produce a commercially valuable machine was to adhere-to theold type of machine, driven by a rack-bar and pinion;

but great difliculties were encountered in attempting to build a machineof twice the capacity of those formerly employed yet of small enoughsize to be portable and capable of being operatedby one man.

In order to increase the capacity of the machine, it became necessary toalso in crease the diameter of the armature-shaft and of thedriving-pinion to properly supportthe armature against the side thrustof the raclebar and to give thenecessary stiffness to said shaft. Withthe increased size of the armature-shaft and pinion it became necessaryto increase the length of the rack-bar to such an. extent that one mancould not operate it. In this larger type of machine, which. it wasattempted to manufacture, as'well as in most of the smaller machinespreviously used, the side thrust of the rack-bar against the pinion andshaft of the armature caused a slight bending -of the armature-shaft,and the armature was caused to unevenly rotate and brought nearer toone'pole than to the other. This resulted in very uneven runninr of thema chine and caused profuse spaflring at the brushes, resulting from thevarying of the width of the air-gap between the armature and the poles.Thus it was found practically inipossible to buildalarger machine thanthose heretofore used While employing the same general design. If theshaft were permitted to remain the same, the armature was not properlysupported and ran very unevenly. if the shaft were increased in size, alarger pinion and longer rack-bar had to be used, and this rendered itno longer possible for one man to operate the machine.

By means of my improved construction i am able to build adeviee of twicethe ca pacity of any heretofore constructed without increasing the sizeof thearmature-shaft'or increasing the length of the rack-bar, and'Ialso reduce to a minimum, if not entirely obviate, all sparking at thebrushes, and secure a great improvement in the smoothnessof any machineof this type heretofore. con structed, but'maystill be'easilytransferred from place to place and operated man. The invention consistsin certain features of construction and combination ofparts, all of.which will be fully set forth hereinafter, and particularly pointed outin the claims.-

Re'ference is to be had to the-accompanying drawings, forming apart ofthis speciii}.

cation, in which similar characters of reference indieatecorrespondingparts in all the figures, in which- Figure 1 is a side elevation of myimproved blasting-machine, one side of the easlng being removed todisclose the operating parts. big. 2 is a plan view showing the end ofthe armature and my improved armatureshaft-supporting means, and Fig. 8is a perspeetive view of the armature-shaft support.

Devices of the type to which my invention belongs customarily comprise arectangular casing 10,01 wood or other suitable material,

and having a partition 11 intermediate its ends and serving to supportthe dynamo. This dynamo comprises an armature 12,

rotating between poles '13 in the upper portion of the casing, saidpoles being supported by the field-coils 14:, resting on the partition11. The top of the casing is provided with binding-posts 15,130 whichthe wires leading to-the fuses are connected, and each bindingpost leadsto the field-coils by means of wires 16 and to a switch in the bottom ofthe casing by means of wires 17. 'A rack-bar 18 is provided for rotatingthe armatureshaft, and this rack-bar extends through openings in the topof the casing and in the partition 11 and engages with the switch inthebottom of the casing. The switch is of any suitable type, and preferablycomprises a spring 19 and a-binding-post 20, normally in contact,whereby as the rack-bar is pushed down into the casing and the armatureis rotated the current generated is short-circuited and may pass freelyfrom one wire 17 to the other wire. As the rack-barreaches the-bottom ofthe casing it presses down upon the. spring 19 and breaks the contactand causes the current to fiow from onebindingpost 15 through theblasting-line to the other binding-post 15. For properly supporting andguiding the rack-bar there is provided a guide-bar 21 parallel to therack bar and in engagement with a perforated bracket 22, carried by thelatter. As

" the casing the armature 12 is rotating at its the circuit through theswitch at the bottom of the casing is normally closed and remains closeduntil the rack-bar 18 almost reaches the end of its downs'troke, theblasting line is thuSShort-circuited and practically 'the blasting-line.Approximately at the" moment the rack-bar reaches the bottom oi greatestspeed, and hence the blasting-line containing the fuses instantlyreceives. themaxirnum current obtainable from the ma- --chine, and thecharges are exploded.

' The armature,- 12 is mounted on a shaft 23 and carries a pinion 2 1,loosely mounted thereon; The oneend of the'pinion is provided with teethwhich engage with oppositely dispose'd teeth on the end of the armature,and at the opposite end of the'pinion there is provided a spring 25,normally holding the teeth of the pinion-in engagement with those of thearmature. By pushing down on the rack-bar 18 the armature is caused'torotate; but upon ulling up on the rackbar the pinion moves ongitudinallyon the shaft and the teeth slip past each other without causing anyreverse rotation of the armature.

In order to support the armature arma- Lure-shaft, and rack-bar, Iprovide the inn proved'member illustrated in Fig. 3. This membercomprises a yoke-casting having longitudinal members 26 upon opoositesides thereof and adapted to be secured to the opposite poles 13.Connecting the two members 26 are two separate and distinct crossbars oryokes, intermediate of which is provided the guideway for the rack-bar.One

of these cross-bars or yokes 27 carries a bearing 28 ofconsiderably-larger sizethan the armature-shaft'ZS and receives thearmature intermediate the teeth and the coil thereof. By making thisbearing as large as convenem a greatly-increased bearing-surface isprovided, and the center portion of the armature may be increased to anysize desired. The second cross-bar or yoke 29 is provided with a bearing30, adapted to receive the end of the armatureshaft, and this bearing isconstructed very much smaller than the bearing 28, the size of saidbearing depending upon the size of the shaft employed. As the mainweight of the armature is supported in the bearing 28 a very small shaftmay be employed and also a inion ofmuch less diameter than would hepossible if the entire weight of the armature were supported on theshaft 23 and this shaft made of a size sufficient to pro erly supportaid armature. Within the si e of the casting intermediate the bearings28 and 30 is provided a guideway 31 for the'rack-bar, whereby the latterclaim as new and desire to secure by Letters other than in alongitudinal (lire/c l ion.

nearer one pole than the other; but by my adapted. to receive the shaftadjacent iLS end,

eraser.

may be supported in a different relationship to the pinion 24 andprevented 'lrom moving As the raeli bar is pushed down to rotaie thearmature there is created a very great side thrust against thearmmere-shaft, and there is a strongtendency for this shaft to bend toone side and bring the armature improved construction wherein thearmature is supported. by a larger bearing intermediate the opening andthe arn'iaiuie and also supported by a second bearing at the end of theshaft no. side movement or bending; of the .arinaturashaft is possible,and the side thrust caused by themoveinent of the racls 1 bar cannotresult in other than a perfectly smooth riinning of the armature. By preventing all. vibration of the arnu rethe sparking at the brushes almostentirely eliminated, and, previously sea-led, I have constructed adevice capable of liring' twice the number of charges of any device ofthis type heretofore constructed, but have still" kept the device Withinthe limits defined by the required portability and easy of operation.

Having thus described my invention, 1

Patent 1. in combination, a rotary armature, poles supported adjacentthereto, a shaft for said armature, a support for said armature andshaft, comprising a slielel oi'i. l'rah'ie havl ing a bearing adapted toreceive the shaft intermediate the armature and the end of lhe shaft,auda second but smaller hearing l a pinion mounted on said shaftintermediate l said. bearings, and a rack-bar in engaeement l with said.pinion and movable in a plane at right angles 'totlie xis of thesl'iaft.

12. In fcoinhination, a re armature, poles supported adj there-to, shaftfor said armature, a support for said and shaft, said support comprisingbearing 1 adapter; to receive theshaft intermediate the armature and theend of the shaft, a second bearing spaced from the first-mentioned airng and adapted to receive the shaftedjacent its end, apinion looselymounted on said shaft inl erined'iale said bearings, means whereby therotation of the pinion causes the rotation of the armature, and arack-oar in engagement With said pinion and movable in plane rightangles to the axis of the shat 3. In combination, a rotary armature,poles supported adj acenft' thereto, a shaft for said armature, a pinionloosely mounted on said shaft, coacting means on said pinion and shaft,whereby the rotation of the pinion in one direction causes thesimultaneous rotation of the armature and shaft, a rack-bar inengagement with said shaft and mow able in a plane at right angles'tothe, iLXiSO'f the shaft, and a support for said armature and shaft,comprising a member having portions l poles, a bea'ing for the shaftintermediate the pinion and the ari'natiir e, a second bearingintermediate the pinion and the outer end of the shaft, and a guidewayfor said rack har.

4. In combination, a rotary armature, a shaft for said arn'iature, alongitudinallyn'iovable pinion on said shaft, said pinion and ai'lnaeurehaving coacting teeth to cause the simultaneous movement of the pinionand armaiure, a rack-bar in engagement with said pinion and movable in aplane at right angles to the axis of the shaft, a bearing for l theshaft intermediate the pinionand the armature, a bearing for the outerend of the shaft, and a guideway for the racl -bar intewith both ofsaid. hearings. v In testimony whereof I have signed my name to thisspecification in the presence of two subscribing witnesses.

GEQRGE ADIN ALLEN; il' itnesses:

it. J. "lliinnss, H. A. liicirean,

iereof secured to and supported hythe said

